Rigid plastic joint for vertical walls



FIG. 1 is a perspective view of a rigid plastic joint for vertical walls showing my new design;

FIG. 2 is a right side elevational view, the left side being a mirror image thereof;

FIG. 3 is an end elevational view thereof; and

FIG. 4 is a top plan view, the bottom being a mirror image thereof. 

The ornamental design for a rigid plastic joint for vertical walls, as shown. 